From: Like Xu <like.xu@linux.intel.com>
To: "Liuxiangdong (Aven,
Cloud Infrastructure Service Product Dept.)"
<liuxiangdong5@huawei.com>
Cc: andi@firstfloor.org, "Fangyi (Eric)" <eric.fangyi@huawei.com>,
Xiexiangyou <xiexiangyou@huawei.com>,
kan.liang@linux.intel.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, wei.w.wang@intel.com,
x86@kernel.org, "Xu, Like" <like.xu@intel.com>
Subject: Re: [PATCH v4 01/16] perf/x86/intel: Add x86_pmu.pebs_vmx for Ice Lake Servers
Date: Fri, 9 Apr 2021 16:46:14 +0800 [thread overview]
Message-ID: <1ba15937-ee3d-157a-e891-981fed8b414d@linux.intel.com> (raw)
In-Reply-To: <60701165.3060000@huawei.com>
Hi Liuxiangdong,
On 2021/4/9 16:33, Liuxiangdong (Aven, Cloud Infrastructure Service Product
Dept.) wrote:
> Do you have any comments or ideas about it ?
>
> https://lore.kernel.org/kvm/606E5EF6.2060402@huawei.com/
My expectation is that there may be many fewer PEBS samples
on Skylake without any soft lockup.
You may need to confirm the statement
"All that matters is that the EPT pages don't get
unmapped ever while PEBS is active"
is true in the kernel level.
Try "-overcommit mem-lock=on" for your qemu.
>
>
> On 2021/4/6 13:14, Xu, Like wrote:
>> Hi Xiangdong,
>>
>> On 2021/4/6 11:24, Liuxiangdong (Aven, Cloud Infrastructure Service
>> Product Dept.) wrote:
>>> Hi，like.
>>> Some questions about this new pebs patches set：
>>> https://lore.kernel.org/kvm/20210329054137.120994-2-like.xu@linux.intel.com/
>>>
>>>
>>> The new hardware facility supporting guest PEBS is only available
>>> on Intel Ice Lake Server platforms for now.
>>
>> Yes, we have documented this "EPT-friendly PEBS" capability in the SDM
>> 18.3.10.1 Processor Event Based Sampling (PEBS) Facility
>>
>> And again, this patch set doesn't officially support guest PEBS on the
>> Skylake.
>>
>>>
>>>
>>> AFAIK， Icelake supports adaptive PEBS and extended PEBS which Skylake
>>> doesn't.
>>> But we can still use IA32_PEBS_ENABLE MSR to indicate general-purpose
>>> counter in Skylake.
>>
>> For Skylake, only the PMC0-PMC3 are valid for PEBS and you may
>> mask the other unsupported bits in the pmu->pebs_enable_mask.
>>
>>> Is there anything else that only Icelake supports in this patches set?
>>
>> The PDIR counter on the Ice Lake is the fixed counter 0
>> while the PDIR counter on the Sky Lake is the gp counter 1.
>>
>> You may also expose x86_pmu.pebs_vmx for Skylake in the 1st patch.
>>
>>>
>>>
>>> Besides, we have tried this patches set in Icelake. We can use pebs(eg:
>>> "perf record -e cycles:pp")
>>> when guest is kernel-5.11, but can't when kernel-4.18. Is there a
>>> minimum guest kernel version requirement?
>>
>> The Ice Lake CPU model has been added since v5.4.
>>
>> You may double check whether the stable tree(s) code has
>> INTEL_FAM6_ICELAKE in the arch/x86/include/asm/intel-family.h.
>>
>>>
>>>
>>> Thanks,
>>> Xiangdong Liu
>>
>
next prev parent reply other threads:[~2021-04-09 8:46 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-29 5:41 [PATCH v4 00/16] KVM: x86/pmu: Add basic support to enable Guest PEBS via DS Like Xu
2021-03-29 5:41 ` [PATCH v4 01/16] perf/x86/intel: Add x86_pmu.pebs_vmx for Ice Lake Servers Like Xu
2021-04-06 3:24 ` Liuxiangdong (Aven, Cloud Infrastructure Service Product Dept.)
2021-04-06 5:14 ` Xu, Like
2021-04-08 1:40 ` Liuxiangdong (Aven, Cloud Infrastructure Service Product Dept.)
2021-04-09 8:33 ` Liuxiangdong (Aven, Cloud Infrastructure Service Product Dept.)
2021-04-09 8:46 ` Like Xu [this message]
2021-04-12 11:26 ` Liuxiangdong (Aven, Cloud Infrastructure Service Product Dept.)
2021-04-12 15:25 ` Andi Kleen
2021-04-14 14:10 ` Liuxiangdong
2021-04-14 14:49 ` Liuxiangdong
2021-04-15 1:38 ` Xu, Like
2021-04-15 2:49 ` Liuxiangdong
2021-04-15 3:23 ` Like Xu
2021-04-06 12:47 ` Andi Kleen
2021-04-07 3:05 ` Liuxiangdong (Aven, Cloud Infrastructure Service Product Dept.)
2021-04-07 14:32 ` Andi Kleen
2021-03-29 5:41 ` [PATCH v4 02/16] perf/x86/intel: Handle guest PEBS overflow PMI for KVM guest Like Xu
2021-04-06 16:22 ` Peter Zijlstra
2021-04-07 0:47 ` Xu, Like
2021-03-29 5:41 ` [PATCH v4 03/16] perf/x86/core: Pass "struct kvm_pmu *" to determine the guest values Like Xu
2021-03-29 5:41 ` [PATCH v4 04/16] KVM: x86/pmu: Set MSR_IA32_MISC_ENABLE_EMON bit when vPMU is enabled Like Xu
2021-03-29 5:41 ` [PATCH v4 05/16] KVM: x86/pmu: Introduce the ctrl_mask value for fixed counter Like Xu
2021-03-29 5:41 ` [PATCH v4 06/16] KVM: x86/pmu: Reprogram guest PEBS event to emulate guest PEBS counter Like Xu
2021-04-07 8:40 ` Peter Zijlstra
2021-03-29 5:41 ` [PATCH v4 07/16] KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS Like Xu
2021-04-07 8:56 ` Peter Zijlstra
2021-04-07 15:25 ` Peter Zijlstra
2021-03-29 5:41 ` [PATCH v4 08/16] KVM: x86/pmu: Add IA32_DS_AREA MSR emulation to manage guest DS buffer Like Xu
2021-04-07 15:39 ` Peter Zijlstra
2021-04-08 5:39 ` Xu, Like
2021-04-08 7:52 ` Peter Zijlstra
2021-04-08 8:44 ` Xu, Like
2021-04-09 7:07 ` Xu, Like
2021-04-09 7:59 ` Peter Zijlstra
2021-04-09 8:30 ` Xu, Like
2021-03-29 5:41 ` [PATCH v4 09/16] KVM: x86/pmu: Add PEBS_DATA_CFG MSR emulation to support adaptive PEBS Like Xu
2021-04-07 15:40 ` Peter Zijlstra
2021-03-29 5:41 ` [PATCH v4 10/16] KVM: x86: Set PEBS_UNAVAIL in IA32_MISC_ENABLE when PEBS is enabled Like Xu
2021-03-29 5:41 ` [PATCH v4 11/16] KVM: x86/pmu: Adjust precise_ip to emulate Ice Lake guest PDIR counter Like Xu
2021-03-29 5:41 ` [PATCH v4 12/16] KVM: x86/pmu: Move pmc_speculative_in_use() to arch/x86/kvm/pmu.h Like Xu
2021-03-29 5:41 ` [PATCH v4 13/16] KVM: x86/pmu: Disable guest PEBS before vm-entry in two cases Like Xu
2021-03-29 5:41 ` [PATCH v4 14/16] KVM: x86/pmu: Add kvm_pmu_cap to optimize perf_get_x86_pmu_capability Like Xu
2021-03-29 5:41 ` [PATCH v4 15/16] KVM: x86/cpuid: Refactor host/guest CPU model consistency check Like Xu
2021-03-29 5:41 ` [PATCH v4 16/16] KVM: x86/pmu: Expose CPUIDs feature bits PDCM, DS, DTES64 Like Xu
2021-04-06 3:19 ` [PATCH v4 00/16] KVM: x86/pmu: Add basic support to enable Guest PEBS via DS Xu, Like
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